Acceleration switch



Feb. 20, 1962 P. R. WEAVER ACCELERATION SWITCH Filed Dec. 23, 1959 &

INVENTOR pAiSTO/V A? Winn 6,?

BY 7 W ATTORNEYS 3,022,393 ACCELERATION SWiTtJH Preston R. Weaver,Nyaclr, N.Y., assignor to Manson Electronics Corporation, a corporationof New York Filed Dec. 23, 1959, Ser. No. 861,538 8 Claims. {CL2lltt-61.45)

This invention relates in general to electrical switches and inparticular to a new and useful acceleration actuated electrical switch,having a functional and structural design particularly adapted forminiature sizes.

The present invention is particularly directed to electrical switcheswhich are actuated by the force of acceleration. Such switches include aresiliently mounted mass which moves to efiect either the making orbreak ing of electrical contact.

The present invention is an improvement in such types of switch andprovides a unidirectional, single axis switch in which an electricalcircuit is adapted to be closed and/or opened at a preset value ofacceleration. An advantage of such a switch construction is that it canbe mounted for response to acceleration in a predetermined direction.The mechanism is such that the parts are not subject to malfunctioningdue tochange of atmospheric conditions and the parts are easy to set foroperation and easily accessible for repair and replacement.

In accordance with the present invention there is provided a switchincluding a cylindrical container having a contact mass-member slidabletherein and biased in one direction by a resilient member ofpredetermined biasing force. The slidable contact mass-member iselectrically connected, preferably, through the walls of the casing to astationary contact. A second contact member is located so that a portionthereof extends within the cylinder and is engageable with a conductiveportion of the mass-member whenever that member has been moved asufficient distance against the force of the restraining resilientmember, such as by an acceleration in the opposite direction.

In a preferred embodiment the mass-member is made hollow and includes aninsulation collar and a conductive collar which are tightly fitted onthe interior thereof. The fixed contact member includes outwardly biasedresilient contact points which are in engagement with one of either ofthe insulation collar or conductive collar. The collars can bepositioned so that either contact is normally madewhen the switch is atrest and is broken upon acceleration of the switch to a predeterminedvalue; or the contact points are normally in contact with the insulationcollar and are moved out of contact therewith upon acceleration of theswitch to a predetermined amount.

Accordingly, it is an object of this invention to provide an improvedacceleration switch.

A further object of the invention is to provide an acceleration switchincluding unidirectional means responsive to changes in acceleration tomake or break an electric circuit.

A further object of the invention is to provide an acceleration switchincluding a conductive material mass slidable in a cylindrical casing ofconductive material and biased in one direction by a coil spring andincluding spaced conductive and insulation portions on said mass, atleast one of which is engaged by a stationary resilient contact member,whereby said mass is movable upon acceleration to present the other ofsaid portions in contact with said stationary contact member.

A further object of the invention is to provide an acceleration switchwhich is simple in design, rugged in construction and economical tomanufacture.

The various features of novelty which characterize the States PatentOflfice 3,022,393 Patented Feb. 20, 1962 invention are pointed out withparticularity in the claims annexed to and forming a part of thisspecification. For a better understanding of the invention, itsoperating advantages and specific objects obtained by its use, referenceshould be had to the accompanying drawings and descriptive matter inwhich there is illustrated and described a preferred embodiment of theinvention.

In the drawings:

FIG. 1 is a longitudinal section of a miniature acceleration switchshown on an enlarged scale;

FIG. 2 is a view similar to FIG. 1 but with the parts in an operativecontact making position; and

FIG. 3 is a section taken in the vicinity of the line 33.

Referring to the drawings in particular, the invention as embodiedtherein includes an outer cylindrical housing generally designated 10which is closed at one end by a cap member 12 which is welded to thehousing as at the location 14. At least an inner face 16 of the housing10 is made of conductive material which is in electrical contact withthe cap member 12 and with a fixed contact terminal 18 which is insertedinto an opening 20 in the cap member. The contact member 18 includes arod portion 22 which is press-fitted into the opening 20 and which makesgood electrical contact with the cap member 12.

In accordance with the invention, there is provided a cylindrical orsleeve-like member or mass generally designated 24 which is slidablewithin the cylindrical housing 10 with portions 25 of the outer wallsthereof in engagement with the inner wall 16 of the cylindrical housing10.

In accordance with the invention, the sliding mass 24 is biased to theright as shown in FIG. 1 by a compression spring 28, one end of which,3%), extends through a small passageway defined in the mass member 24and is secured thereto as by soldering; and the other end of whichextends into a small opening 32 in a disc-shaped cap piece 34 which isafiixed to this end of the housing 10 by soldering as at 35. The coilspring 28 is centered over an outstanding portion 36 of the cap piece 34and biases the mass 24 to the right.

The cap 12 includes a large central opening which receives a fixedcontact member and terminal generally designated 38, inluding a centralcylindrical portion 37 of insulation material. The contact 38 issoldered to housing 10 as at 39. The contact member and terminal 38includes a terminal portion 40 at the exterior of the housing 10 and acontact portion generally designated 42 which extends through thecylindrical portion 37 and into the housing It and a hollowed portion ofthe mass member 24.

The contact member portion 42 includes a plurality of angularly spacedresilient contacts 44 having their inner ends held by a coil spring orwound wire 46 which is soldered and encapsulated by an epoxy resinmaterial 48 and a resin dip 49. The other ends 44 are curved and arebiased outwardly or upwardly by the coil spring 46 into contact with aninsulation material collar member 50 which is press-fitted into theinterior of the hollowed portion of the mass 24. A second collar member52 of conductive material is located adjacent the collar member 50 andis also press-fitted into the hollowed portion of the mass 24 formovement therewith.

After the parts have been tightly sealed together, by soldering at thejoints, the interior of the cylinder is evacuated of air and an inertgas is directed into the cylinder through a passage 54 and a metal plug56 which is thereafter sealed by crimping the outer end. Thus, anymovement of the mass 24' is gas dampened with a gas whosecharacteristics are well known when subject to various ambientconditions. The contact and terminal member 38 is normally anchored inposition as by solder- 9 ing around the edges at 39 after the switch iscalibrated by locating the contacts 4 2 and anchoring the contact memberwith a set screw as which extends through the member 37 and into contactwith the contact and terminal member 4i). In the case where set screw seis provided, adjustment may be made in respect to the location of thecontacts 44 in order to change the acceleration force which will actuatethe switch. In this latter case the member 38 would not be soldered inplace and it is provided with line indications to provide a scalesetting for the acceleration actuating value. The latter would beindicated by the reading on the scale on the member which aligns withthe edge of the member 12.

The switch may be set to operate as indicated in FIG. 1 in which case inthe non-actuated position the contacts 44 are in contact with theinsulation collar 5i; on the the ss 24. In this position when one lineof an electric circuit is connc ted to the terminal 18 and the other isconnected to the terminal as, electrical contact will not be made andthe circuit will be opened. When the device in which the switch ismounted is moved through an acceleration of a predetermined amount, themass 24 will compress the spring 28, and, when a sulficient force ofacceleration has been applied, the contacts will contact the conductivecollar 52 as the mass 24 is moved against the spring '23 to complete thecircuit from the terminal mem ber 18, the inner face 16 of the housinglid and the mass 24 to the terminal (See P16. 2.)

It should be appreciated that the positions of the collars 5d and 52 maybe reversed so that the contacts ddwill complete the electrical circuitwhen a switch is not subject to an acceleration force, and willdisconnect the electrical circuit w ran the switch is subject to suchforce. T he actual size of the switch of the present invention may beless than 1 /2 in length and less than /2" in diameter, and theinstrument may still be machined for precise actuation at a preselectedacceleration. The switch is of simple rugged construction which permitsreliable operation of the parts with very little likelihood of failure.By choosing the correct coil spring it is possible to obtain repeatedperformance for many hours of operation. The switch has been tested andsubiected to shock conditions of 50 times gravity without causing anydamage to the operating mechanism.

Thus the invention provides a reliable lightweight, acceleration switchwhich may be made accurately in minute sizes for actuating equipment inresponse to a preset acceleration force without the need of el ctroniccircuitry.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventionprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. An acceleration switch comprising an outer hollow housing memberhaving a longitudinal axis and having a first contact terminal inelectrical contact with at least the interior wall of said housing, asecond contact terminal extending into said housing and disposed in aplane coplanar with said axis, and a mass member having a conductiveportion in contact with the internal wall of said housing and havingaligned conductive and non-conductive portions independently engageablewith said second fixed contact member along a longitudinal locusparallel to said axis, means to bias said mass in one direction to bringsaid second fixed contact member into engagement with one of saidconductive and non-conductive portions of said mass member, said massmember being movable against said biasing means upon acceleration tomove the other of said conductive and non-conductive portions intocontact with said Contact member.

2. A switch comprising a hollow housing member having a longitudinalaxis and an interior wall of conductive material, a first contactterminal extending out of said housing and being in electrical contactwith said interior wall, a second contact terminal having a portionextending out of said housing and a portion extending into said housingand said portion being disposed in a plane coplanar with said axis, amass slidable in said housing including a conductive portion in contactwith said interior wall and separate conductive and non-conductivecontact portions in alignment with said second contact, the coplanarcontact portion of the second contact terminal operating to engage theseparate conductive and -conductive contact portions along the linearlocus parallel to said axis, and resilient means biasing said mass inone direction to bring one of said conductive and non-conductiveportions into contact with said portion of the second co tact member,wherein said mass is movable against the force of said biasing to bringthe other of said conductive and non-conductive contact portions intocontact with said portion of the second contact memher on said linearlocus.

3. A switch according to claim 2, wherein said mass is a cylindricalmember and said conductive and nonconductive contact portions aredefined on the interior walls thereof as co-axial cylinders defining acylindrical 106k for the linear paths of movement of said co-planarportions of the second contact terminal.

4. A switch according to claim 2, wherein said mass is a hollowcylindrical member and wherein said resilient means includes a springbiased between an end wall of said housing and said cylindrical member.

5. An acceleration switch comprising a cylindrical housing of conductivematerial having a longitudinal main axis, a hollow cylindrical mass ofconductive material slidable within said housing with the outer wallsthereof in contact with the interior walls of said housing, means to b ssaid cylindrical member in one direction in said housing, a firstcontact member including resilient contact portions extending into saidhousing and into the in ."ior of said hollow cylindrical mass, saidcontact memher being insulated from said housing, a second contactmember electrically connected to said housing and extending outwardlytherefrom, a collar of insulation material positioned in said hollowcylindrical mass and having the inner surface of said collar in a'gnment with said contact member on a linear locus parallel to saidaxis, a collar oi conductive material adiacent said insulation materialcollar and having its inner surface also in alignment with said contactmember on said linear locus, said mass being biased by said spring to alocation br'nging said second contact member into engagement w..n saidinsulation material collar, said mass being movable against the force ofsaid biasing upon an acceleration to position the conductive collar inelectrical contact with said contact whereby the electrical circuit iscompieted through said. collar, said mass and said housing to sai firstcontact terminal.

6. An acceleration switch according to claim 5 wherein said firstcontact member resilient contact portions include a plurality of rodmembers having curved outer ends disposed in angularly spacedrelationship with each curved outer end disposed within its own plane,and means to bias the inner ends of said contact portions together tohold the outer ends in proper planar positions to direct the desiredpressure forces of those outer ends against the inner strfaces of thecollars.

7. An acceleration switch comprising an outer hollow housing memberhaving a generally longitudinal axis and having a first contact terminalin electrical contact with at least the interior wall of said housing, asecond adjustable contact terminal having a resilient portion extendinginto said housing by a preselected amount, and a mass member having aconductive portion in contact with the internal wall of said housing andhaving aligned axially conductive and non-conductive portionsindependently engageable with said resilient portion of said secondfixed contact member along a linear locus parallel to said 6 axis, meansto bias said mass in one direction to bring tion of said second contactmember in respect to said said second fixed contact member intoengagement with housing. one of said conductive and non-conductiveportions of said mass member, said mass member being movable ReferencesCited in the file of this P against said biasing means upon accelerationto move 5 the other of said conductive and non-conductive portionsUNITED STATES PATENTS into contact with said contact member. 2,424,390Ferris July 22, 1947 8. An acceleration switch according to claim 7,wherein 2,850,590 Marks et a1 Sept. 2, 1958 said second contact memberincludes a portion slidable 2,930,863 Pasieka Mar. 29, 1960 in saidhousing, and means to indicate the relative posi- 10

